Nowadays, the operations of mixing, granulating and regulating the particle size of power material are carried out in a broad range of fields, such as pharmaceuticals and foodstuffs. Therefore, the particle size adjustment operation carried out in a product manufacture process is an important unit operation in improving the quality of the powder based granules, improving the flowability during fluidized drying and improving the handling properties.
Here, in powder based granules disintegrating and sizing devices which have been used in the prior art, the particle size is regulated by the use of screens. Consequently, there is a possibility that with continuous use, the screen will become worn and damaged, and worn particles or broken shards of the screen may become mixed into the product powder based granules. Furthermore, in the case of a wet material, depending on the physical properties of the material being processed, blocking of the screen mesh holes occurs due to the adherence of material, and there is a risk that material being processed may become clogged into the screen. Moreover, there has also been a problem in that particles which are of a suitable particle size are also disintegrated due to the force of impact of the disintegrating blade, and hence a large amount of fine-particles are generated, resulting in a decline in the yield rate.
Therefore, the present applicants have previously developed a powder based granules disintegrating and sizing device which does not use a screen, and have filed patent applications in this respect (Japanese Patent Application Publication No. 2000-117131 (hereinafter, Patent Document 1), Japanese Patent Application Publication No. 2005-131609 (hereinafter, Patent Document 2), and WO 2004/085069 A1 publication (hereinafter, Patent Document 3).
These powder based granules disintegrating and sizing devices are devices which regulate the size of the particles of a wet or dry material supplied via a material supply port by passing the material through a prescribed settlement region, a gap region being formed by providing a rotating body and an opposing surface section which opposes the rotating body and is separated from same by a prescribed gap, inside a casing which constitutes the device, and this gap region being constituted as a particle size adjustment region which allows the passage of particles that conform to the prescribed gap setting but does not permit the passage of particles that do not conform to same, in such a manner that the particles which are not able to pass through the gap region are brought into contact with the opposing surface section due to the rotational movement of the rotating body, in the input section or surface section of the gap region, and are thereby disintegrated so as to be able to pass through the gap region and are then output through the output port.
In the gap region, the rotating body and the opposing surface section are provided with a planar section or a linear section which is set so as to form a narrowest gap section, in such a manner that the particles are disintegrated in this narrowest gap region or in the vicinity thereof.
More specifically, in the powder based granules disintegrating and sizing devices described in Patent Document 1 and Patent Document 2, a rotating body fixed to a drive shaft provided in a vertical direction is formed in a substantially circular conical shape, the casing is formed in a substantially hollow circular conical shape, and a settlement region for the powder based granules material is formed between the inner wall of the casing and the circumferential surface of the rotating body, the narrowest gap region being formed by the lower circumferential edge of the rotating body and the inner wall of the casing.
Furthermore, in the powder based granules disintegrating and sizing device described in Patent Document 3, a drive shaft is provided in a horizontal direction inside a casing, and a plurality of circular plates (rotating bodies) fixed at intervals to the drive shaft are provided, together with sizing stators, which are disposed to the lower side of the circular plates so as to create resistance with respect to the surface of the plate in the circumferential edge portion thereof and which have an inclined surface that reduces the gap with respect to the plate surface of the circular plate toward the circumferential edge plurality of same, gap sections in which the powder based granules particles settle being formed by the plate surfaces of the circular plates and the inclined surfaces of the sizing stator, and disintegrating and sizing sections being formed by the narrowest gap regions between the circumferential edges of the circular plates and the sizing stators.
However, firstly, in the powder based granules disintegrating and sizing devices described in Patent Document 1 and Patent Document 2, since the drive shaft is disposed in the vertical direction, then the direction of the centrifugal force applied to the powder based granules particles by the rotating body which is caused to rotated by the drive shaft is a horizontal direction which is perpendicular to the direction of gravity. Therefore, the powder based granules particles, from the time that they are supplied and subjected to disintegrating and sizing until the time that they are output, receive forces in various directions from the rotating body, the internal walls of the casing, and the like, thus acquiring a complicated motion, and hence a smooth flow of powder based granules particles is not formed inside those machines. As a result of this, in a disintegrating and sizing process for a dried powder based granules, for example, the settlement time of the powder based granules inside the device becomes long and there is a tendency for a large number of fine-particles to be generated. Furthermore, in a disintegrating and sizing process for a wet powder based granules material, since a smooth flow cannot be formed, then there is a drawback in that a large amount of material adheres to the internal walls of the device.
Moreover, in the powder based granules disintegrating and sizing device described in Patent Document 3, a sizing stator is provided only on the lower side of the circular plates, and therefore no disintegrating and sizing action occurs on the upper side of the circular plates, and the efficiency is poor. Furthermore, since the powder based granules material being processed is supplied from the upper side of the circular plates, then it rebounds due to the centrifugal force of the circular plates and does not enter readily into the device. Moreover, since the drive shaft disposed in the horizontal direction has a structure which is supported at either end, then the size of the device increases, and furthermore, there is a risk that oil and the like from the supporting sections will enter into the casing, in other words, into the powder based granules processing chamber, thus making this device unsuitable for the processing of powder based granules where infiltration of impurities is to be avoided, such as pharmaceuticals, food products, or the like.
Furthermore, in all of the powder based granules disintegrating and sizing devices described in the Patent Documents mentioned above, the gap in the sizing section, in other words, the particle size, is adjusted by means of an operator observing the particle size of the product and then selecting a member of a suitable thickness from a plurality of types of ring members or size regulating stators having different thicknesses, and installing the selected ring member or size regulating stator. Consequently, this adjustment task takes time, and skill and physical strength are required in order to replace the ring member or size regulating stator. Furthermore, since it is necessary to prepare a plurality of ring members and size regulating stators having different thicknesses, then the management of these members or stators becomes complicated.